1. Field of the Invention
This invention relates to apparatus for processing photographic materials.
2. Background of the Prior Art
It has heretofore been proposed to provide roller transport apparatus for processing photographic materials in web form in tanks containing chemicals in solution and washing liquid, and in which the web is moved downwardly in the tank, then at or near the bottom of the tank is turned and moved upwardly for delivery to another tank or for drying. One of the problems which has been encountered is in the turnaround at the bottom of the tank.
It has been proposed, as part of the turnaround apparatus, to provide fixed guide plates or shoes, as shown in the U.S. Patents to Kunz, No. 3,072,310; Hope et al., Nos. 3,532,048, 3,656,676 and 3,952,610. Such guide plates are usually ribbed or corrugated and have a tendency to scratch or streak the web being processed.
It has also been proposed, as part of the turnaround apparatus to guide the web with rollers as shown in the U.S. Patents to Kunz, No. 3,067,919; Russell et al., Nos., 3,025,779 and 3,147,090; Krehbiel, No. 3,345,928; Hope et al., Nos. 3,952,610, 3,989,176, 4,026,451, 4,079,635 and 4,118,998. With the use of such guide rollers it is important that the centers of the shafts be properly located to provide a smooth advance of the web with avoidance of scratching of the web. A wide radius is required to accommodate the guide rollers with consequent lack of compactness. The use of nip rollers is troublesome because of the difficulty in maintaining constant pressure on the web to avoid slipping because of insufficient pressure and to avoid pinching and bruising which can occur with excessive pressure.